Add an 'Idle Wake Ups' metric to the Linux task manager, implement backend.

base/process/process_metrics_mac.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/process/process_metrics.h"
 
 #include <mach/mach.h>
 #include <mach/mach_vm.h>
 #include <mach/shared_region.h>
 #include <sys/sysctl.h>
@@ skipping 281 matching lines @@
   mach_msg_type_number_t power_info_count = TASK_POWER_INFO_COUNT;
   kern_return_t kr = task_info(task,
                                TASK_POWER_INFO,
                                reinterpret_cast<task_info_t>(&power_info_data),
                                &power_info_count);
   if (kr != KERN_SUCCESS) {
     // Most likely cause: |task| is a zombie, or this is on a pre-10.8.4 system
     // where TASK_POWER_INFO isn't supported yet.
     return 0;
   }
-  uint64_t absolute_idle_wakeups = power_info_data.task_platform_idle_wakeups;
-
-  TimeTicks time = TimeTicks::Now();
-
-  if (last_absolute_idle_wakeups_ == 0) {
-    // First call, just set the last values.
-    last_idle_wakeups_time_ = time;
-    last_absolute_idle_wakeups_ = absolute_idle_wakeups;
-    return 0;
-  }
-
-  int64 wakeups_delta = absolute_idle_wakeups - last_absolute_idle_wakeups_;
-  int64 time_delta = (time - last_idle_wakeups_time_).InMicroseconds();
-  if (time_delta == 0) {
-    NOTREACHED();
-    return 0;
-  }
-
-  last_idle_wakeups_time_ = time;
-  last_absolute_idle_wakeups_ = absolute_idle_wakeups;
-
-  // Round to average wakeups per second.
-  const int kMicrosecondsPerSecond = 1000 * 1000;
-  return (wakeups_delta * kMicrosecondsPerSecond + time_delta/2) / time_delta;
+  return CalculateIdleWakeupsPerSecond(
+      power_info_data.task_platform_idle_wakeups);
 }
 
 bool ProcessMetrics::GetIOCounters(IoCounters* io_counters) const {
   return false;
 }
 
 ProcessMetrics::ProcessMetrics(ProcessHandle process,
                                ProcessMetrics::PortProvider* port_provider)
     : process_(process),
       last_system_time_(0),
@@ skipping 21 matching lines @@
                                      &count);
   if (kr != KERN_SUCCESS) {
     MACH_DLOG(WARNING, kr) << "host_statistics";
     return 0;
   }
 
   return (data.active_count * PAGE_SIZE) / 1024;
 }
 
 }  // namespace base